using System;
using System.Drawing;
using System.Windows.Forms;

namespace CustomWindowButtons
{
    public partial class Form1 : Form
    {
        // 記錄鼠標拖動時的起始位置
        private Point mouseDownPoint = Point.Empty;

        public Form1()
        {
            InitializeComponent();
            // 窗體初始化設置
            InitFormSettings();
            // 綁定按鈕事件
            BindButtonEvents();
        }

        /// <summary>
        /// 初始化窗體設置（移除系統(tǒng)邊框、設置窗體樣式）
        /// </summary>
        private void InitFormSettings()
        {
            // 移除系統(tǒng)默認窗口邊框和標題欄
            this.FormBorderStyle = FormBorderStyle.None;
            // 設置窗體默認大小
            this.Size = new Size(800, 600);
            // 居中顯示
            this.StartPosition = FormStartPosition.CenterScreen;

            // 自定義按鈕樣式初始化（可選，簡化外觀）
            btnMin.Size = new Size(40, 30);
            btnMax.Size = new Size(40, 30);
            btnClose.Size = new Size(40, 30);
            btnMin.Text = "—";
            btnMax.Text = "□";
            btnClose.Text = "×";
            btnMin.Font = new Font("Arial", 12, FontStyle.Bold);
            btnMax.Font = new Font("Arial", 12, FontStyle.Bold);
            btnClose.Font = new Font("Arial", 12, FontStyle.Bold);

            // 排列按鈕（窗體右上角）
            btnClose.Location = new Point(this.Width - 45, 5);
            btnMax.Location = new Point(this.Width - 90, 5);
            btnMin.Location = new Point(this.Width - 135, 5);
        }

        /// <summary>
        /// 綁定按鈕的點擊事件和鼠標懸浮/離開事件
        /// </summary>
        private void BindButtonEvents()
        {
            // 最小化按鈕點擊事件
            btnMin.Click += BtnMin_Click;
            // 最大化/還原按鈕點擊事件
            btnMax.Click += BtnMax_Click;
            // 關閉按鈕點擊事件
            btnClose.Click += BtnClose_Click;

            // 可選：添加按鈕鼠標懸浮效果，提升交互體驗
            btnMin.MouseEnter += Button_MouseEnter;
            btnMax.MouseEnter += Button_MouseEnter;
            btnClose.MouseEnter += Button_MouseEnter;
            btnMin.MouseLeave += Button_MouseLeave;
            btnMax.MouseLeave += Button_MouseLeave;
            btnClose.MouseLeave += Button_MouseLeave;
        }

        #region 按鈕事件處理
        /// <summary>
        /// 最小化按鈕點擊事件
        /// </summary>
        private void BtnMin_Click(object sender, EventArgs e)
        {
            // 調用窗體內置方法，將窗口最小化到任務欄
            this.WindowState = FormWindowState.Minimized;
        }

        /// <summary>
        /// 最大化/還原按鈕點擊事件
        /// </summary>
        private void BtnMax_Click(object sender, EventArgs e)
        {
            // 判斷當前窗口狀態(tài)，切換最大化/還原
            if (this.WindowState == FormWindowState.Maximized)
            {
                // 還原窗口默認大小
                this.WindowState = FormWindowState.Normal;
                btnMax.Text = "□"; // 更新按鈕文本
            }
            else
            {
                // 最大化窗口
                this.WindowState = FormWindowState.Maximized;
                btnMax.Text = "■"; // 更新按鈕文本
            }

            // 窗口狀態(tài)變化后，重新調整按鈕位置（避免最大化后按鈕偏移）
            AdjustButtonPosition();
        }

        /// <summary>
        /// 關閉按鈕點擊事件
        /// </summary>
        private void BtnClose_Click(object sender, EventArgs e)
        {
            // 調用窗體內置方法，關閉當前窗體
            this.Close();
        }

        /// <summary>
        /// 鼠標懸浮按鈕時，更改按鈕背景色
        /// </summary>
        private void Button_MouseEnter(object sender, EventArgs e)
        {
            Button btn = sender as Button;
            if (btn != null)
            {
                // 關閉按鈕懸浮時設置紅色背景，其他按鈕設置淺灰色
                btn.BackColor = btn == btnClose ? Color.LightCoral : Color.LightGray;
            }
        }

        /// <summary>
        /// 鼠標離開按鈕時，恢復按鈕默認背景色
        /// </summary>
        private void Button_MouseLeave(object sender, EventArgs e)
        {
            Button btn = sender as Button;
            if (btn != null)
            {
                btn.BackColor = SystemColors.Control;
            }
        }
        #endregion

        #region 輔助方法
        /// <summary>
        /// 調整按鈕位置（適配窗口最大化/還原狀態(tài)）
        /// </summary>
        private void AdjustButtonPosition()
        {
            btnClose.Location = new Point(this.Width - 45, 5);
            btnMax.Location = new Point(this.Width - 90, 5);
            btnMin.Location = new Point(this.Width - 135, 5);
        }

        /// <summary>
        /// 實現(xiàn)窗體拖動功能（重寫鼠標按下/移動/松開事件）
        /// </summary>
        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            // 記錄鼠標按下時的坐標（相對于窗體）
            if (e.Button == MouseButtons.Left)
            {
                mouseDownPoint = new Point(e.X, e.Y);
            }
        }

        protected override void OnMouseMove(MouseEventArgs e)
        {
            base.OnMouseMove(e);
            // 鼠標左鍵按住且起始位置有效時，拖動窗體
            if (e.Button == MouseButtons.Left && mouseDownPoint != Point.Empty)
            {
                // 計算窗體新位置
                this.Location = new Point(
                    this.Left + (e.X - mouseDownPoint.X),
                    this.Top + (e.Y - mouseDownPoint.Y)
                );
            }
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            // 鼠標松開后，重置起始位置
            mouseDownPoint = Point.Empty;
        }
        #endregion

        /// <summary>
        /// 窗口大小改變時，重新調整按鈕位置（適配手動拉伸窗口）
        /// </summary>
        protected override void OnResize(EventArgs e)
        {
            base.OnResize(e);
            if (this.WindowState != FormWindowState.Minimized)
            {
                AdjustButtonPosition();
            }
        }
    }
}